27results about How to "Reduce phase noise" patented technology

A crystal oscillator and a method for reducing phase noise are provided. The crystal oscillator may include a crystal oscillator core circuit, a first bias circuit, and a phase noise reduction circuit. The first bias circuit is coupled to the output of the crystal oscillator core circuit, and the phase noise reduction circuit is also coupled to the output of the crystal oscillator core circuit. In operation, the crystal oscillator core circuit is configured to generate a sine wave. The first bias circuit is configured to provide a first voltage level as a bias voltage for the sine wave. The phase noise reduction circuit is configured to reset the bias voltage of the sine wave in response to the voltage level of the sine wave exceeding a specific voltage range. Using this method, the phase noise of the crystal oscillator can be reduced.

A fractional-N phase-locked loop (PLL) and its charge pump control method are provided. The fractional-N PLL includes a first current source, a first phase frequency detector (PFD), a second current source, a second PFD, and a frequency divider clock controller. The first current source provides a first current. The first PFD generates a first detection signal based on a first frequency divider clock to control the first current source, wherein the first frequency divider clock is generated based on an oscillation clock with an oscillation period. The second current source provides a second current. The second PFD generates a second detection signal based on a second frequency divider clock to control the second current source. The frequency divider controller controls the second frequency divider clock based on a variable delay relative to the first frequency divider clock, wherein the variable delay is an integer multiple of the oscillation period. Using this method, phase noise can be reduced.

The present disclosure provides a communication radar integrated optical fiber remote system and a phase locking method. A remote antenna unit is configured to receive a reflected microwave signal, and modulate the amplitude of the microwave signal to obtain an initial optical carrier signal. A dispersion compensation unit is connected with the remote antenna unit and configured to perform dispersion compensation on the initial optical carrier signal to obtain an optical carrier signal. A central unit is connected with the dispersion compensation unit and configured to perform phase locking using the received optical carrier signal to obtain an output optical signal. The frequency of the output optical signal is the same as that of the optical carrier signal, and the phase of the output optical signal is the same as that of the optical carrier signal. A signal output unit is connected with the central unit and configured to output the output optical signal. The present disclosure realizes the consistency of the frequency and the phase synchronization of the output optical signal and the optical carrier signal, realizes low phase noise carrier recovery, and improves the communication and radar performance.

This invention discloses a reconfigurable multi-mode ring oscillator, relating to the field of radio frequency integrated circuit design technology. The reconfigurable multi-mode ring oscillator includes multiple delay units and a switching network. The switching network is used to dynamically reconfigure the connection topology of the multiple delay units to switch between three modes. In the first mode, the switching network connects all delay units end-to-end to form a 6-stage ring oscillator. In the second mode, the switching network divides the multiple delay units into two parallel 3-stage sub-loops, and the corresponding core nodes of the two 3-stage sub-loops are coupled to each other through the switching network. In the third mode, the switching network divides the multiple delay units into three parallel 2-stage sub-loops, and the corresponding core nodes of the three 2-stage sub-loops are coupled to each other through the switching network. This provides a novel ring oscillator structure that can increase the tuning range and effectively suppress noise.

The invention provides a pulsed eddy current detection device and detection method based on roller pair adjustment, and relates to the technical field of nondestructive detection. The device comprises a supporting frame, a roller pair, a telescopic driving mechanism, a detection probe, a sliding adjusting mechanism, a distance measuring unit and a control unit. The control unit maintains the constant distance between the detection probe and the surface of the detected rod body based on a feedback signal of the distance measuring unit; based on the distance and the roller state signal, a telescopic driving mechanism is controlled to adjust the posture of the roller pair, so that the axis of the roller pair is aligned with the axis of the measured rod body; and when a preset spacing stability condition and an alignment condition are met, controlling the detection probe to transmit a pulsed eddy current excitation signal to the detected rod body, and receiving and outputting an eddy current response signal for defect identification. The double-shaft lift-off effect is actively inhibited through dynamic closed-loop control, the stability and accuracy of a detection signal are guaranteed, and then the recognition rate and detection reliability of the rod body surface and near-surface defects are remarkably improved.

The invention provides a method for automatically generating a pixelated resonant cavity of an oscillator based on knowledge-driven reverse design. The method comprises the following steps: determining a topological region range of VCO resonant cavity design; determining a reverse design target; a priori knowledge driving pixel matrix drawing strategy is established, pixelated inductor topological structure drawing is completed in the topological region based on the drawing strategy, and a primary pixelated inductor topological structure quality factor and a secondary pixelated inductor topological structure quality factor are calculated; according to a reverse design target, searching a Q value of a primary pixelated inductance topological structure from a binary n * n matrix assembly at a given target frequency, and meanwhile, achieving a maximized optimal solution to obtain an optimal pixel topological structure; and constructing the voltage-controlled oscillator in combination with the optimal pixel topological structure. According to the method, batch automatic simulation and optimization of the optimal resonant cavity structure can be realized, and compared with manual design, the time cost is saved, and meanwhile, the performance is further improved.

This invention provides a crystal oscillator and a method for suppressing phase noise of the same. The crystal oscillator may include a crystal oscillator core circuit, a bias circuit coupled to the output of the crystal oscillator core circuit, a pulse wave buffer coupled to the output of the crystal oscillator core circuit, and a phase noise suppression circuit coupled to the output of the crystal oscillator core circuit. The crystal oscillator core circuit can generate a sine wave. The bias circuit can provide a bias voltage for the sine wave. The pulse wave buffer can generate a pulse wave according to the sine wave. The phase noise suppression circuit can generate a reset signal containing at least one reset pulse for resetting the bias voltage. Furthermore, a reset signal is generated without calibrating at least one reset pulse to the zero-crossing point of the sine wave.

This application provides a timing control device, system, and method for frequency-scanning radar based on frequency synthesizer and digital logic modules. The frequency synthesizer module serves as the synchronization source and timing reference source for the operating modes of the frequency-scanning radar system. In terms of system hardware architecture, it achieves coherent synchronization between the RF sub-module and the digital logic module. At the RF end, the SYNC signal is used to broaden the pulses of each sub-module, thereby forming the gate signals for each module's corresponding operating mode, which are distributed only by the digital logic module. At the digital end, edge and pulse width detection of the SYNC and MODE signals triggers the sampling and digital signal processing timing. The entire system uses the signal generated by the frequency synthesizer module as the reference, achieving high precision and low phase noise while reducing the external RF cables of the digital logic module. It also achieves strong coupling between the RF and digital ends, which is beneficial for FPGA on-chip resource optimization and timing convergence, reducing design verification costs and subsequent expansion costs.

The application provides a radio frequency source circuit and a laser frequency shift lock cavity signal generation method, which can be applied to the field of cold atom optical lattice clock technology. The radio frequency source circuit comprises a control sub-circuit, a phase-locked loop sub-circuit and an output power control sub-circuit. The control sub-circuit is used for receiving a digital control instruction from an upper computer and taking a synchronous clock as a working clock, performing amplitude-phase conversion and phase waveform conversion in parallel based on preset modulation data carried by the digital control instruction, and outputting a phase control word and a phase demodulation signal. The phase-locked loop sub-circuit is used for frequency multiplication of a reference clock and outputting a clock signal suitable for the working frequency of a frequency synthesizer as the working reference clock of the frequency synthesizer. The frequency synthesizer is used for taking the working reference clock as a frequency reference, realizing phase synchronization by combining the synchronous clock, and adjusting the phase of an output signal based on the phase control word. The output power control sub-circuit is used for adjusting the power of the output signal of the frequency synthesizer based on preset power modulation data to output a laser frequency shift lock cavity signal.

The application discloses a kind of based on in-phase injection coupling quadrature enhanced ring oscillator, belong to radio frequency integrated circuit technical field, comprising: ring oscillator circuit and quadrature coupler circuit;Ring oscillator circuit is used to generate oscillation signal, including cascaded two differential ring oscillator basic units, and each stage differential ring oscillator basic unit includes input pair transistor and negative resistance pair transistor;Quadrature coupler circuit includes coupling transistor: Q1, Q2 and Q3, four differential output nodes of first stage differential ring oscillator basic unit and second stage differential ring oscillator basic unit are connected respectively, and in-phase injection coupling structure is formed.Through introducing in-phase injection coupling structure in quadrature enhanced ring oscillator, high-precision phase locking and low phase noise are realized Collaborative optimization, on the premise of not consuming static power consumption, the phase difference of multiple-phase output signal is stably locked in by pure switch operation.

The invention provides a reference source and a satellite communication system.The reference source comprises an atomic clock, a first phase-locked loop, a low-frequency crystal oscillator, a frequency doubling filter circuit, a second phase-locked loop, a high-frequency crystal oscillator and an output device.A miniaturized design scheme is adopted, an ultra-thin rubidium clock, a constant-temperature crystal oscillator and an ultra-low phase noise crystal oscillator are arranged in the reference source; the system has the characteristics of small size and low cost, meets the application requirements of a miniaturized or highly integrated scene, and has a wide prospect; the multi-stage frequency synthesis technology is adopted, so that the output reference signal has the characteristics of high speed, stability and low phase noise, the requirements of the fields of time-frequency measurement, radar detection and the like on the reference source are met, and the application range is wide.

The application discloses a kind of phase correction method and system for structured light stripe profile projection, when boundary is identified, including the process of twice boundary identification, edge extraction is carried out by gray scale chart in initial boundary identification, in the second boundary identification, edge information extraction is carried out by phase calculation, boundary is identified by gray scale chart and phase diagram two directions, improve the accuracy of boundary identification, further the result of twice boundary identification is fused, so that the phase of stable area is not disturbed by jump pixel, ensure the accuracy of boundary division, based on the region after division, filtering processing is carried out to stable area, reduce the loss of feature information, provide reference information for the correction of unstable area, reduce error transmission, when the unstable area is compensated for error with stable area as reference, phase noise can be reduced, so as to reduce point cloud noise and improve precision.

The application discloses a soliton optical frequency comb and an optical microwave signal generation device, which comprises an optical source unit and an input light control unit, is suitable for obtaining amplified first pump laser, amplified second pump laser and amplified third pump laser; a micro resonant cavity unit comprising a micro resonant cavity, is suitable for generating a soliton optical frequency comb through a nonlinear four-wave mixing parametric oscillation process in the micro resonant cavity by using the amplified first pump laser; is suitable for compensating optical power changes caused by frequency mismatch of the amplified first pump laser by using the amplified second pump laser in the micro resonant cavity; and is suitable for suppressing thermal mechanical vibration noise of the micro resonant cavity based on optical force refrigeration effect by using the amplified third pump laser, so as to suppress phase noise of the soliton optical frequency comb; and a soliton optical frequency comb monitoring unit comprising a microwave signal generation module, the microwave signal generation module is suitable for generating an optical microwave signal by using the soliton optical frequency comb.

The present application relates to a kind of self-injection terahertz light frequency comb system, wherein, terahertz quantum cascade laser is as light frequency comb source, beat frequency signal generated by self beat frequency is transmitted into first T-type biasing device;First T-type biasing device is used to transmit beat frequency signal to wave divider;Wave divider is used to divide beat frequency signal into two ways, one way is transmitted to circulator and participates in self injection, another way is connected to spectrum analyzer and carries out real-time detection;Circulator is used to keep the one-way transmission of beat frequency signal participating in self injection in loop;Phase shifter is used to phase match beat frequency signal participating in self injection;Second T-type biasing device is used to inject phase-matched beat frequency signal into terahertz quantum cascade laser;Spectrum analyzer is used to detect the self-injection beat frequency signal obtained in real time.The present application can improve the stability of system, meet the requirement as high-frequency optoelectronic oscillator.

The utility model discloses a low noise continuous wave modulation laser drive source for high speed laser range finder, the utility model discloses a clock chip of CDCEL925 series is used to generate clock signal, and generates fundamental wave main vibration signal with this, wherein, compared with remaining frequency synthesis technique, it can produce the clock signal of lower phase noise, so, can generate the fundamental wave main vibration signal of low phase noise, simultaneously, through low noise direct current voltage module, the bias current of laser is generated, and it is combined with the fundamental wave main vibration signal of low phase noise through ac coupling, then can constitute the laser drive source of low phase noise, based on this, then can effectively reduce the random error of phase difference measurement, in addition, the utility model discloses still through optical power feedback module to carry out the power feedback of laser, and through integral regulator to feedback and adjust the bias current of laser loop, so, then can realize the transient stability of optical power in the modulation process, to further improve the ranging precision.

This invention discloses a voltage-controlled delay unit circuit, comprising: PMOS1 and PMOS3 with their sources connected to a power supply and their gates connected to a control voltage; PMOS1 with its drain connected to the source of PMOS2 and PMOS3 with its drain connected to the source of PMOS4; PMOS2 with its drain connected to the drain of NMOS1, the gate of PMOS4, and the gate of NMOS3; PMOS2 and NMOS1 with their gates connected to the input terminal IN and PMOS4 and NMOS3 with their drains connected to the output terminal OUT; NMOS1 with its source connected to the drain of NMOS2, NMOS2 with its gate connected to a bias voltage and its source grounded; NMOS3 with its source connected to the drain of NMOS4, NMOS4 with its gate connected to a bias voltage and its source grounded; PMOS5 and PMOS6 with their sources connected to a power supply and their gates connected to a control voltage, and their drains connected to the drains of NMOS1 and NMOS3 respectively; and NMOS5 and NMOS6 with their drains connected to the drains of PMOS1 and PMOS3 respectively, and their gates connected to a bias voltage and their sources grounded. This invention significantly shortens the level inversion time of the inverter, greatly reduces the circuit's sensitivity to power supply noise, substrate noise, and thermal noise, thereby directly reducing the phase noise and clock jitter of the delay phase-locked loop (DLL) output clock.

The frequency adjustment circuit and method for a voltage-controlled oscillator (VCO) with temperature compensation function according to this application embodiment first generates a voltage signal through a control voltage generation branch and transmits it to the second signal control terminal of the VCO. The output signal of the VCO is divided by a phase-locked loop (PLL) branch and input to the frequency calibration branch along with a reference clock. A temperature sensor collects temperature data from the chip and sends the temperature data to the frequency calibration branch. The frequency calibration branch outputs a control signal to the first control signal terminal of the VCO based on the divided clock of the VCO's output signal, the reference clock, and the temperature data, so that the operating frequency of the VCO is the target frequency. The PLL branch locks the VCO operating at the target frequency. This solution avoids the PTAT voltage generation circuit and corresponding varactor diodes involved in traditional temperature compensation circuits, reduces phase noise, effectively achieves temperature compensation adjustment of the VCO, and realizes frequency locking.

A high frequency yttrium iron garnet oscillator (10) is described that comprises a coplanar yttrium iron garnet resonator (12). The coplanar yttrium iron garnet resonator (12) has an yttrium iron garnet sphere (28), a coplanar coupling structure (22) and a coplanar waveguide (24). The coplanar coupling structure (22) is integrated with the coplanar waveguide (24). The coplanar coupling structure (22) is coupled to the yttrium iron garnet sphere (28). Further, a method of manufacturing a high frequency yttrium iron garnet oscillator is described.

The invention discloses a voltage-controlled frequency source for embedded current vector synthesis frequency multiplication. An intermediate frequency differential clock signal output end of a multi-frequency output dual-core inverse F voltage-controlled oscillator is connected with a differential clock input end of a differential-single-ended output buffer and a differential clock input end of an orthogonal / 2 frequency divider; the output end of the differential-single-ended output buffer is connected with the intermediate-frequency clock signal output end, and the four-phase output end of the orthogonal / 2 frequency divider is connected with the corresponding phase in the orthogonal four-phase low-frequency clock signal output end. A first high-frequency differential clock signal output end and a second high-frequency differential clock signal output end of the multi-frequency output dual-core inverse F voltage-controlled oscillator are respectively connected with a first differential clock signal input end and a second differential clock signal input end of the current vector synthesis frequency multiplier; the voltage-controlled frequency source has the characteristics of low phase noise, low hardware overhead and low extra power consumption, and the frequency multiplier has low influence on the spurious characteristic of an output frequency signal.

The application discloses a time delay interference laser phase noise compensation method and device for optical frequency domain reflection, and comprises the following steps: obtaining a linear sweep signal light based on a signal source; obtaining a first heterodyne signal through a measurement interferometer, and obtaining a second heterodyne signal through a reference interferometer; and processing the first heterodyne signal and the second heterodyne signal by using a time delay interference algorithm, so that direct compensation of laser phase noise is realized; and obtaining a strain signal based on the direct compensation of the laser phase noise. Through compensation of the laser phase noise, high-precision measurement of the strain signal can be realized at a distance far beyond the coherence length of the light source.

The application belongs to the field of integrated circuit technology design, and relates to a passive and crystal-free GFSK transmitter chip, which comprises a radio frequency energy collection module, a power management module, a clock recovery module and an open-loop modulation transmitter module, the radio frequency energy collection module is used for wireless power supply, the power management module controls a power switch of the transmitter chip according to a power supply voltage value, when the power switch is opened, the power management module supplies power to the open-loop modulation transmitter module, the clock recovery module provides a reference frequency for the open-loop modulation transmitter module, and the open-loop modulation transmitter module multiplies the reference frequency to a radio frequency frequency required for transmission and transmits a data signal. The transmitter chip has the advantages of low power consumption and small size, is suitable for wireless sensor network nodes, and has strong commercial value.

The invention discloses a photon terahertz signal modulation and demodulation method, and relates to the technical field of terahertz communication and radio over fiber communication. Conjugate angle modulation is realized at a transmitting end through a dual-wavelength generator and an optical phase modulator, a target signal is converted into an angle modulation optical signal with a constant envelope characteristic, and preliminary spectrum spreading is realized. And the two paths of conjugate angle modulation optical signals pass through a photoelectric detector to realize further expansion of the signal frequency spectrum and generate broadband terahertz signals. And a receiving end completes signal demodulation through an improved angle demodulation module and recovers a target signal. Compared with the prior art, higher angle modulation depth is supported, the generated terahertz signal is low in phase noise and flexible and adjustable in carrier frequency, and more efficient angle modulation and more stable angle demodulation processing in a photon terahertz transmission system can be realized, so that the signal-to-noise ratio of the terahertz signal is improved, and the signal-to-noise ratio of the terahertz signal is improved. The method is used for assisting long-distance and high-fidelity transmission and the like.

This invention belongs to the field of integrated circuits and relates to a low-phase-noise bonded wire inductor-capacitor voltage-controlled oscillator, comprising: a cross-coupled transistor, a voltage-controlled variable capacitor, a switched capacitor array, a differential bonded wire inductor, a tail current transistor, an on-chip inductor, and a filter capacitor; the switched capacitor array, the voltage-controlled variable capacitor, and the differential bonded wire inductor are connected in parallel; the two ends of the differential bonded wire inductor are connected to one end of the cross-coupled transistor, the other end of the cross-coupled transistor is connected to one end of the on-chip inductor, the other end of the on-chip inductor is connected to the drain of the tail current transistor and one end of the filter capacitor, and the source of the tail current transistor and the other end of the filter capacitor are grounded; this invention achieves a voltage-controlled oscillator through a high-Q differential bonded wire inductor, increasing the Q value by 80% compared to an on-chip inductor; by adding an LC filter composed of a switched capacitor array, a voltage-controlled variable capacitor, and a differential bonded wire inductor between the drain of the tail current source and the source of the cross-coupled transistor, bias current power supply noise is reduced.

An oscillator circuit comprises an oscillator transistor (Q1) having respective first, second, and control terminals, the oscillator transistor being arranged to generate a microwave oscillating signal at the first terminal. A surface integrated waveguide resonator (Y1) is connected to the second terminal of the oscillator transistor (Q1). An active bias circuit portion (202) comprising a negative feedback arrangement is between the first terminal of the oscillator transistor (Q1) and the control terminal of the oscillator transistor (Q1), the active bias circuit portion being arranged to supply a bias current to the control terminal of the oscillator transistor (Q1). The bias current is dependent on a voltage at the first terminal of the oscillator transistor (Q1) multiplied by a negative gain.

The application discloses a microwave source, which solves the problems of phase noise and stability of the microwave source, and comprises a microwave reference source, a filter cavity, an integrator, a microwave frequency multiplication unit, a directional coupler and a microwave antenna, wherein the microwave reference source outputs a voltage control signal; the filter cavity receives the voltage control signal and filters the voltage control signal to obtain a filtered signal one; the integrator is used for integrating the received filtered signal one to obtain an integrated signal; the microwave frequency multiplication unit is used for frequency multiplying the received integrated signal to obtain a microwave frequency multiplication signal; the directional coupler is used for directionally coupling the received microwave frequency multiplication signal to obtain a microwave signal one and a microwave signal two; and the microwave antenna receives the microwave signal two to obtain an antenna signal. The application can greatly improve the frequency stability of the microwave frequency band, reduce the phase noise, and has simple circuit design, low cost and small size.

The invention relates to the technical field of radio frequency electronics, and discloses a multi-channel radio frequency signal source device and an implementation method, and the device comprises a satellite receiver, a frequency reference source, a clock signal source, a multi-channel radio frequency signal source, a frequency monitoring module and a phase monitoring module. The frequency reference source locks a satellite signal generation benchmark; the clock signal source generates a driving clock based on a reference; the multi-path radio frequency signal source generates multi-path radio frequency signals by using a driving clock based on a direct digital frequency synthesis principle; the phase monitoring module measures signal phase difference through IQ phase discrimination and feeds back the signal phase difference, and realizes closed-loop phase locking in cooperation with multiple paths of radio frequency signal sources. A two-stage driving framework is adopted, synchronous frequency modulation of multiple paths of signals can be achieved by adjusting a clock, the phase relation is not changed, and automatic phase recovery after independent frequency modulation can be achieved through phase compensation. The invention has the advantages of continuous frequency modulation phase, stable amplitude, no need of automatic level control, low phase noise, high phase resolution and the like.

This invention discloses a dual-comb absolute distance measurement system based on Raman gain modulation of a single-frequency laser. The system includes an optical frequency comb, a single-frequency laser, a rare-earth-doped amplifier, an optical coupler, a wavelength division multiplexer, a Raman gain fiber, an optical circulator, an optical collimator, a target, an optical bandpass filter, and a photodetector. The single-frequency laser is split into two paths, each coupled to an amplified optical frequency comb and then into the Raman gain fiber, generating two highly coherent Raman gain modulated dual combs: a signal comb and a local oscillator comb. The signal comb is divided into two groups; one group is reflected from the target and carries distance information, coupled to the other group and then to the local oscillator comb. After aliasing is eliminated by an optical bandwidth filter, the signal is collected by the photodetector, and the phase is de-encapsulated to calculate the distance. Due to the Raman gain modulation process, simple optical longitudinal mode stabilization and carrier wavelength readout can be achieved, ultimately using interferometry to achieve nanometer-level ranging accuracy.